diff --git a/api/baseapi.cpp b/api/baseapi.cpp
index 457c7ab61f..e1dec94c3e 100644
--- a/api/baseapi.cpp
+++ b/api/baseapi.cpp
@@ -46,6 +46,7 @@
 #include <string>
 #include <iterator>
 #include <fstream>
+#include <memory> // std::unique_ptr
 
 #include "allheaders.h"
 
@@ -1267,9 +1268,8 @@ char* TessBaseAPI::GetUTF8Text() {
   ResultIterator *it = GetIterator();
   do {
     if (it->Empty(RIL_PARA)) continue;
-    char *para_text = it->GetUTF8Text(RIL_PARA);
-    text += para_text;
-    delete []para_text;
+    const std::unique_ptr<const char[]> para_text(it->GetUTF8Text(RIL_PARA));
+    text += para_text.get();
   } while (it->Next(RIL_PARA));
   char* result = new char[text.length() + 1];
   strncpy(result, text.string(), text.length() + 1);
@@ -1393,6 +1393,7 @@ static void AddBoxToTSV(const PageIterator* it, PageIteratorLevel level,
  * Image name/input_file_ can be set by SetInputName before calling
  * GetHOCRText
  * STL removed from original patch submission and refactored by rays.
+ * Returned string must be freed with the delete [] operator.
  */
 char* TessBaseAPI::GetHOCRText(int page_number) {
   return GetHOCRText(NULL, page_number);
@@ -1405,6 +1406,7 @@ char* TessBaseAPI::GetHOCRText(int page_number) {
  * Image name/input_file_ can be set by SetInputName before calling
  * GetHOCRText
  * STL removed from original patch submission and refactored by rays.
+ * Returned string must be freed with the delete [] operator.
  */
 char* TessBaseAPI::GetHOCRText(ETEXT_DESC* monitor, int page_number) {
   if (tesseract_ == NULL || (page_res_ == NULL && Recognize(monitor) < 0))
@@ -1539,11 +1541,10 @@ char* TessBaseAPI::GetHOCRText(ETEXT_DESC* monitor, int page_number) {
     if (bold) hocr_str += "<strong>";
     if (italic) hocr_str += "<em>";
     do {
-      const char *grapheme = res_it->GetUTF8Text(RIL_SYMBOL);
+      const std::unique_ptr<const char[]> grapheme(res_it->GetUTF8Text(RIL_SYMBOL));
       if (grapheme && grapheme[0] != 0) {
-        hocr_str += HOcrEscape(grapheme);
+        hocr_str += HOcrEscape(grapheme.get());
       }
-      delete []grapheme;
       res_it->Next(RIL_SYMBOL);
     } while (!res_it->Empty(RIL_BLOCK) && !res_it->IsAtBeginningOf(RIL_WORD));
     if (italic) hocr_str += "</em>";
@@ -1576,6 +1577,7 @@ char* TessBaseAPI::GetHOCRText(ETEXT_DESC* monitor, int page_number) {
 /**
  * Make a TSV-formatted string from the internal data structures.
  * page_number is 0-based but will appear in the output as 1-based.
+ * Returned string must be freed with the delete [] operator.
  */
 char* TessBaseAPI::GetTSVText(int page_number) {
   if (tesseract_ == NULL || (page_res_ == NULL && Recognize(NULL) < 0))
@@ -1661,7 +1663,7 @@ char* TessBaseAPI::GetTSVText(int page_number) {
     if (res_it->IsAtFinalElement(RIL_BLOCK, RIL_WORD)) bcnt++;
 
     do {
-      tsv_str += res_it->GetUTF8Text(RIL_SYMBOL);
+      tsv_str += std::unique_ptr<const char[]>(res_it->GetUTF8Text(RIL_SYMBOL)).get();
       res_it->Next(RIL_SYMBOL);
     } while (!res_it->Empty(RIL_BLOCK) && !res_it->IsAtBeginningOf(RIL_WORD));
     tsv_str += "\n";  // end of row
@@ -1700,8 +1702,9 @@ const int kMaxBytesPerLine = kNumbersPerBlob * (kBytesPer64BitNumber + 1) + 1 +
 
 /**
  * The recognized text is returned as a char* which is coded
- * as a UTF8 box file and must be freed with the delete [] operator.
+ * as a UTF8 box file.
  * page_number is a 0-base page index that will appear in the box file.
+ * Returned string must be freed with the delete [] operator.
  */
 char* TessBaseAPI::GetBoxText(int page_number) {
   if (tesseract_ == NULL ||
@@ -1718,7 +1721,7 @@ char* TessBaseAPI::GetBoxText(int page_number) {
   do {
     int left, top, right, bottom;
     if (it->BoundingBox(RIL_SYMBOL, &left, &top, &right, &bottom)) {
-      char* text = it->GetUTF8Text(RIL_SYMBOL);
+      const std::unique_ptr</*non-const*/ char[]> text(it->GetUTF8Text(RIL_SYMBOL));
       // Tesseract uses space for recognition failure. Fix to a reject
       // character, kTesseractReject so we don't create illegal box files.
       for (int i = 0; text[i] != '\0'; ++i) {
@@ -1727,10 +1730,9 @@ char* TessBaseAPI::GetBoxText(int page_number) {
       }
       snprintf(result + output_length, total_length - output_length,
                "%s %d %d %d %d %d\n",
-               text, left, image_height_ - bottom,
+               text.get(), left, image_height_ - bottom,
                right, image_height_ - top, page_number);
       output_length += strlen(result + output_length);
-      delete [] text;
       // Just in case...
       if (output_length + kMaxBytesPerLine > total_length)
         break;
@@ -1755,8 +1757,8 @@ const int kLatinChs[] = {
 
 /**
  * The recognized text is returned as a char* which is coded
- * as UNLV format Latin-1 with specific reject and suspect codes
- * and must be freed with the delete [] operator.
+ * as UNLV format Latin-1 with specific reject and suspect codes.
+ * Returned string must be freed with the delete [] operator.
  */
 char* TessBaseAPI::GetUNLVText() {
   if (tesseract_ == NULL ||
@@ -1981,9 +1983,9 @@ bool TessBaseAPI::AdaptToWordStr(PageSegMode mode, const char* wordstr) {
   PageSegMode current_psm = GetPageSegMode();
   SetPageSegMode(mode);
   SetVariable("classify_enable_learning", "0");
-  char* text = GetUTF8Text();
+  const std::unique_ptr<const char[]> text(GetUTF8Text());
   if (debug) {
-    tprintf("Trying to adapt \"%s\" to \"%s\"\n", text, wordstr);
+    tprintf("Trying to adapt \"%s\" to \"%s\"\n", text.get(), wordstr);
   }
   if (text != NULL) {
     PAGE_RES_IT it(page_res_);
@@ -2023,7 +2025,6 @@ bool TessBaseAPI::AdaptToWordStr(PageSegMode mode, const char* wordstr) {
       tesseract_->EnableLearning = true;
       tesseract_->LearnWord(NULL, word_res);
     }
-    delete [] text;
   } else {
     success = false;
   }
diff --git a/api/baseapi.h b/api/baseapi.h
index 5263b2d8d7..1efa76ba8e 100644
--- a/api/baseapi.h
+++ b/api/baseapi.h
@@ -591,6 +591,7 @@ class TESS_API TessBaseAPI {
    * monitor can be used to
    *  cancel the recognition
    *  receive progress callbacks
+   * Returned string must be freed with the delete [] operator.
    */
   char* GetHOCRText(ETEXT_DESC* monitor, int page_number);
 
@@ -598,28 +599,30 @@ class TESS_API TessBaseAPI {
    * Make a HTML-formatted string with hOCR markup from the internal
    * data structures.
    * page_number is 0-based but will appear in the output as 1-based.
+   * Returned string must be freed with the delete [] operator.
    */
   char* GetHOCRText(int page_number);
 
   /**
    * Make a TSV-formatted string from the internal data structures.
    * page_number is 0-based but will appear in the output as 1-based.
+   * Returned string must be freed with the delete [] operator.
    */
   char* GetTSVText(int page_number);
 
   /**
    * The recognized text is returned as a char* which is coded in the same
-   * format as a box file used in training. Returned string must be freed with
-   * the delete [] operator.
+   * format as a box file used in training.
    * Constructs coordinates in the original image - not just the rectangle.
    * page_number is a 0-based page index that will appear in the box file.
+   * Returned string must be freed with the delete [] operator.
    */
   char* GetBoxText(int page_number);
 
   /**
    * The recognized text is returned as a char* which is coded
-   * as UNLV format Latin-1 with specific reject and suspect codes
-   * and must be freed with the delete [] operator.
+   * as UNLV format Latin-1 with specific reject and suspect codes.
+   * Returned string must be freed with the delete [] operator.
    */
   char* GetUNLVText();
 
diff --git a/api/pdfrenderer.cpp b/api/pdfrenderer.cpp
index 93b336691f..c388bb5af6 100644
--- a/api/pdfrenderer.cpp
+++ b/api/pdfrenderer.cpp
@@ -20,6 +20,7 @@
 #include "config_auto.h"
 #endif
 
+#include <memory> // std::unique_ptr
 #include "allheaders.h"
 #include "baseapi.h"
 #include "math.h"
@@ -460,10 +461,10 @@ char* TessPDFRenderer::GetPDFTextObjects(TessBaseAPI* api,
     STRING pdf_word("");
     int pdf_word_len = 0;
     do {
-      const char *grapheme = res_it->GetUTF8Text(RIL_SYMBOL);
+      const std::unique_ptr<const char[]> grapheme(res_it->GetUTF8Text(RIL_SYMBOL));
       if (grapheme && grapheme[0] != '\0') {
         GenericVector<int> unicodes;
-        UNICHAR::UTF8ToUnicode(grapheme, &unicodes);
+        UNICHAR::UTF8ToUnicode(grapheme.get(), &unicodes);
         char utf16[kMaxBytesPerCodepoint];
         for (int i = 0; i < unicodes.length(); i++) {
           int code = unicodes[i];
@@ -473,7 +474,6 @@ char* TessPDFRenderer::GetPDFTextObjects(TessBaseAPI* api,
           }
         }
       }
-      delete []grapheme;
       res_it->Next(RIL_SYMBOL);
     } while (!res_it->Empty(RIL_BLOCK) && !res_it->IsAtBeginningOf(RIL_WORD));
     if (word_length > 0 && pdf_word_len > 0 && fontsize > 0) {
@@ -570,14 +570,13 @@ bool TessPDFRenderer::BeginDocumentHandler() {
 
   // CIDTOGIDMAP
   const int kCIDToGIDMapSize = 2 * (1 << 16);
-  unsigned char *cidtogidmap = new unsigned char[kCIDToGIDMapSize];
+  const std::unique_ptr</*non-const*/ unsigned char[]> cidtogidmap(new unsigned char[kCIDToGIDMapSize]);
   for (int i = 0; i < kCIDToGIDMapSize; i++) {
     cidtogidmap[i] = (i % 2) ? 1 : 0;
   }
   size_t len;
   unsigned char *comp =
-      zlibCompress(cidtogidmap, kCIDToGIDMapSize, &len);
-  delete[] cidtogidmap;
+      zlibCompress(cidtogidmap.get(), kCIDToGIDMapSize, &len);
   n = snprintf(buf, sizeof(buf),
                "5 0 obj\n"
                "<<\n"
@@ -670,10 +669,9 @@ bool TessPDFRenderer::BeginDocumentHandler() {
   fseek(fp, 0, SEEK_END);
   long int size = ftell(fp);
   fseek(fp, 0, SEEK_SET);
-  char *buffer = new char[size];
-  if (fread(buffer, 1, size, fp) != size) {
+  const std::unique_ptr</*non-const*/ char[]> buffer(new char[size]);
+  if (fread(buffer.get(), 1, size, fp) != size) {
     fclose(fp);
-    delete[] buffer;
     return false;
   }
   fclose(fp);
@@ -686,13 +684,11 @@ bool TessPDFRenderer::BeginDocumentHandler() {
                ">>\n"
                "stream\n", size, size);
   if (n >= sizeof(buf)) {
-    delete[] buffer;
     return false;
   }
   AppendString(buf);
   objsize  = strlen(buf);
-  AppendData(buffer, size);
-  delete[] buffer;
+  AppendData(buffer.get(), size);
   objsize += size;
   AppendString(endstream_endobj);
   objsize += strlen(endstream_endobj);
@@ -887,12 +883,11 @@ bool TessPDFRenderer::AddImageHandler(TessBaseAPI* api) {
   AppendPDFObject(buf);
 
   // CONTENTS
-  char* pdftext = GetPDFTextObjects(api, width, height);
-  long pdftext_len = strlen(pdftext);
-  unsigned char *pdftext_casted = reinterpret_cast<unsigned char *>(pdftext);
+  const std::unique_ptr</*non-const*/ char[]> pdftext(GetPDFTextObjects(api, width, height));
+  const long pdftext_len = strlen(pdftext.get());
   size_t len;
   unsigned char *comp_pdftext =
-      zlibCompress(pdftext_casted, pdftext_len, &len);
+      zlibCompress(reinterpret_cast<unsigned char *>(pdftext.get()), pdftext_len, &len);
   long comp_pdftext_len = len;
   n = snprintf(buf, sizeof(buf),
                "%ld 0 obj\n"
@@ -901,7 +896,6 @@ bool TessPDFRenderer::AddImageHandler(TessBaseAPI* api) {
                ">>\n"
                "stream\n", obj_, comp_pdftext_len);
   if (n >= sizeof(buf)) {
-    delete[] pdftext;
     lept_free(comp_pdftext);
     return false;
   }
@@ -910,7 +904,6 @@ bool TessPDFRenderer::AddImageHandler(TessBaseAPI* api) {
   AppendData(reinterpret_cast<char *>(comp_pdftext), comp_pdftext_len);
   objsize += comp_pdftext_len;
   lept_free(comp_pdftext);
-  delete[] pdftext;
   const char *b2 =
       "endstream\n"
       "endobj\n";
diff --git a/api/renderer.cpp b/api/renderer.cpp
index e683149381..822e5244e7 100644
--- a/api/renderer.cpp
+++ b/api/renderer.cpp
@@ -19,6 +19,7 @@
 #include "config_auto.h"
 #endif
 
+#include <memory> // std::unique_ptr
 #include <string.h>
 #include "baseapi.h"
 #include "genericvector.h"
@@ -122,13 +123,12 @@ TessTextRenderer::TessTextRenderer(const char *outputbase)
 }
 
 bool TessTextRenderer::AddImageHandler(TessBaseAPI* api) {
-  char* utf8 = api->GetUTF8Text();
+  const std::unique_ptr<const char[]> utf8(api->GetUTF8Text());
   if (utf8 == NULL) {
     return false;
   }
 
-  AppendString(utf8);
-  delete[] utf8;
+  AppendString(utf8.get());
 
   bool pageBreak = false;
   api->GetBoolVariable("include_page_breaks", &pageBreak);
@@ -186,11 +186,10 @@ bool TessHOcrRenderer::EndDocumentHandler() {
 }
 
 bool TessHOcrRenderer::AddImageHandler(TessBaseAPI* api) {
-  char* hocr = api->GetHOCRText(imagenum());
+  const std::unique_ptr<const char[]> hocr(api->GetHOCRText(imagenum()));
   if (hocr == NULL) return false;
 
-  AppendString(hocr);
-  delete[] hocr;
+  AppendString(hocr.get());
 
   return true;
 }
@@ -219,11 +218,10 @@ bool TessTsvRenderer::BeginDocumentHandler() {
 bool TessTsvRenderer::EndDocumentHandler() { return true; }
 
 bool TessTsvRenderer::AddImageHandler(TessBaseAPI* api) {
-  char* tsv = api->GetTSVText(imagenum());
+  const std::unique_ptr<const char[]> tsv(api->GetTSVText(imagenum()));
   if (tsv == NULL) return false;
 
-  AppendString(tsv);
-  delete[] tsv;
+  AppendString(tsv.get());
 
   return true;
 }
@@ -236,11 +234,10 @@ TessUnlvRenderer::TessUnlvRenderer(const char *outputbase)
 }
 
 bool TessUnlvRenderer::AddImageHandler(TessBaseAPI* api) {
-  char* unlv = api->GetUNLVText();
+  const std::unique_ptr<const char[]> unlv(api->GetUNLVText());
   if (unlv == NULL) return false;
 
-  AppendString(unlv);
-  delete[] unlv;
+  AppendString(unlv.get());
 
   return true;
 }
@@ -253,11 +250,10 @@ TessBoxTextRenderer::TessBoxTextRenderer(const char *outputbase)
 }
 
 bool TessBoxTextRenderer::AddImageHandler(TessBaseAPI* api) {
-  char* text = api->GetBoxText(imagenum());
+  const std::unique_ptr<const char[]> text(api->GetBoxText(imagenum()));
   if (text == NULL) return false;
 
-  AppendString(text);
-  delete[] text;
+  AppendString(text.get());
 
   return true;
 }
diff --git a/ccmain/paragraphs.cpp b/ccmain/paragraphs.cpp
index c7d21a9192..a8ef87be2c 100644
--- a/ccmain/paragraphs.cpp
+++ b/ccmain/paragraphs.cpp
@@ -21,6 +21,7 @@
 #endif
 
 #include <ctype.h>
+#include <memory> // std::unique_ptr
 
 #include "genericvector.h"
 #include "helpers.h"
@@ -2446,8 +2447,8 @@ void InitializeRowInfo(bool after_recognition,
     return;
   }
   info->text = "";
-  char *text = it.GetUTF8Text(RIL_TEXTLINE);
-  int trailing_ws_idx = strlen(text);  // strip trailing space
+  const std::unique_ptr<const char[]> text(it.GetUTF8Text(RIL_TEXTLINE));
+  int trailing_ws_idx = strlen(text.get());  // strip trailing space
   while (trailing_ws_idx > 0 &&
          // isspace() only takes ASCII
          ((text[trailing_ws_idx - 1] & 0x80) == 0) &&
@@ -2460,7 +2461,6 @@ void InitializeRowInfo(bool after_recognition,
     for (int i = 0; i < trailing_ws_idx; i++)
       info->text += text[i];
   }
-  delete []text;
 
   if (info->text.size() == 0) {
     return;
diff --git a/ccstruct/ocrblock.cpp b/ccstruct/ocrblock.cpp
index ad7893b05a..19f2aecbfd 100644
--- a/ccstruct/ocrblock.cpp
+++ b/ccstruct/ocrblock.cpp
@@ -18,6 +18,7 @@
  **********************************************************************/
 
 #include <stdlib.h>
+#include <memory> // std::unique_ptr
 #include "blckerr.h"
 #include "ocrblock.h"
 #include "stepblob.h"
@@ -380,9 +381,8 @@ void BLOCK::compute_row_margins() {
     TBOX row_box = row->bounding_box();
     int left_y = row->base_line(row_box.left()) + row->x_height();
     int left_margin;
-    ICOORDELT_LIST *segments = lines.get_line(left_y);
-    LeftMargin(segments, row_box.left(), &left_margin);
-    delete segments;
+    const std::unique_ptr</*non-const*/ ICOORDELT_LIST> segments_left(lines.get_line(left_y));
+    LeftMargin(segments_left.get(), row_box.left(), &left_margin);
 
     if (row_box.top() >= drop_cap_bottom) {
       int drop_cap_distance = row_box.left() - row->space() - drop_cap_right;
@@ -394,9 +394,8 @@ void BLOCK::compute_row_margins() {
 
     int right_y = row->base_line(row_box.right()) + row->x_height();
     int right_margin;
-    segments = lines.get_line(right_y);
-    RightMargin(segments, row_box.right(), &right_margin);
-    delete segments;
+    const std::unique_ptr</*non-const*/ ICOORDELT_LIST> segments_right(lines.get_line(right_y));
+    RightMargin(segments_right.get(), row_box.right(), &right_margin);
     row->set_lmargin(left_margin);
     row->set_rmargin(right_margin);
   }
diff --git a/ccstruct/pdblock.cpp b/ccstruct/pdblock.cpp
index cf3289f2e7..4dde3988d0 100644
--- a/ccstruct/pdblock.cpp
+++ b/ccstruct/pdblock.cpp
@@ -18,6 +18,7 @@
  **********************************************************************/
 
 #include          <stdlib.h>
+#include          <memory> // std::unique_ptr
 #include          "allheaders.h"
 #include          "blckerr.h"
 #include          "pdblock.h"
@@ -140,9 +141,9 @@ Pix* PDBLK::render_mask(const FCOORD& rerotation, TBOX* mask_box) {
     // rasterized interior. (Runs of interior pixels on a line.)
     PB_LINE_IT *lines = new PB_LINE_IT(&image_block);
     for (int y = box.bottom(); y < box.top(); ++y) {
-      ICOORDELT_LIST* segments = lines->get_line(y);
+      const std::unique_ptr</*non-const*/ ICOORDELT_LIST> segments(lines->get_line(y));
       if (!segments->empty()) {
-        ICOORDELT_IT s_it(segments);
+        ICOORDELT_IT s_it(segments.get());
         // Each element of segments is a start x and x size of the
         // run of interior pixels.
         for (s_it.mark_cycle_pt(); !s_it.cycled_list(); s_it.forward()) {
@@ -154,7 +155,6 @@ Pix* PDBLK::render_mask(const FCOORD& rerotation, TBOX* mask_box) {
                       xext, 1, PIX_SET, NULL, 0, 0);
         }
       }
-      delete segments;
     }
     delete lines;
   } else {
diff --git a/ccstruct/polyblk.cpp b/ccstruct/polyblk.cpp
index b5ca2e1212..bae881b1ff 100644
--- a/ccstruct/polyblk.cpp
+++ b/ccstruct/polyblk.cpp
@@ -20,6 +20,7 @@
 #include <ctype.h>
 #include <math.h>
 #include <stdio.h>
+#include <memory> // std::unique_ptr
 #include "elst.h"
 #include "polyblk.h"
 
@@ -273,7 +274,6 @@ void POLY_BLOCK::fill(ScrollView* window, ScrollView::Color colour) {
   inT16 y;
   inT16 width;
   PB_LINE_IT *lines;
-  ICOORDELT_LIST *segments;
   ICOORDELT_IT s_it;
 
   lines = new PB_LINE_IT (this);
@@ -281,9 +281,9 @@ void POLY_BLOCK::fill(ScrollView* window, ScrollView::Color colour) {
 
   for (y = this->bounding_box ()->bottom ();
   y <= this->bounding_box ()->top (); y++) {
-    segments = lines->get_line (y);
+    const std::unique_ptr</*non-const*/ ICOORDELT_LIST> segments(lines->get_line (y));
     if (!segments->empty ()) {
-      s_it.set_to_list (segments);
+      s_it.set_to_list (segments.get());
       for (s_it.mark_cycle_pt (); !s_it.cycled_list (); s_it.forward ()) {
         // Note different use of ICOORDELT, x coord is x coord of pixel
         // at the start of line segment, y coord is length of line segment
diff --git a/textord/scanedg.cpp b/textord/scanedg.cpp
index 0430843619..89b7c31a7f 100644
--- a/textord/scanedg.cpp
+++ b/textord/scanedg.cpp
@@ -19,6 +19,8 @@
 
 #include "scanedg.h"
 
+#include <memory> // std::unique_ptr
+
 #include "allheaders.h"
 #include "edgloop.h"
 
@@ -93,7 +95,6 @@ void make_margins(                         //get a line
                   inT16 y                  //line coord
                  ) {
   PB_LINE_IT *lines;
-  ICOORDELT_LIST *segments;      //bits of a line
   ICOORDELT_IT seg_it;
   inT32 start;                   //of segment
   inT16 xext;                    //of segment
@@ -101,9 +102,9 @@ void make_margins(                         //get a line
 
   if (block->poly_block () != NULL) {
     lines = new PB_LINE_IT (block->poly_block ());
-    segments = lines->get_line (y);
+    const std::unique_ptr</*non-const*/ ICOORDELT_LIST> segments(lines->get_line (y));
     if (!segments->empty ()) {
-      seg_it.set_to_list (segments);
+      seg_it.set_to_list (segments.get());
       seg_it.mark_cycle_pt ();
       start = seg_it.data ()->x ();
       xext = seg_it.data ()->y ();
@@ -122,7 +123,6 @@ void make_margins(                         //get a line
       for (xindex = left; xindex < right; xindex++)
         pixels[xindex - left] = margin;
     }
-    delete segments;
     delete lines;
   }
   else {