Make try_fgetc() prepend clearerr() for fgetc() versions that need it.

diff --git a/src/common/readwrite.c b/src/common/readwrite.c
index c2c970d292cb9579d5e6fddc64eb733ac3524246..045bc4fbbc89f80ff2044bc971e98251488d1681 100644 (file)
--- a/src/common/readwrite.c
+++ b/src/common/readwrite.c
@@ -4,7 +4,7 @@
 #include <stddef.h> /* size_t */
 #include <stdint.h> /* uint8_t, uint16_t, uint32_t, UINT32_MAX */
 #include <stdio.h> /* FILE, fseek(), sprintf(), fgets(), fgetc(), ferror(),
-                    * fputc(), fwrite(), fclose(), fopen()
+                    * fputc(), fwrite(), fclose(), fopen(), clearerr()
                     */
 #include <string.h> /* strlen() */
 #include <unistd.h> /* for access(), unlink() */
@@ -53,6 +53,7 @@ extern void try_fputc(uint8_t c, FILE * file, char * f)
 
 extern int try_fgetc(FILE * file, char * f)
 {
+    clearerr(file); /* OSX' (BSD?) fgetc() needs this to undo previous EOFs. */
     int test = fgetc(file);
     exit_trouble(EOF == test && ferror(file), f, "fgetc()");
     return test;

diff --git a/src/common/readwrite.h b/src/common/readwrite.h
index 4aebdbc9b1d1fc3e94cad5b9898d51399da6b310..b61230fb59487ba05f0feed3a05de66bb0ab0dcb 100644 (file)
--- a/src/common/readwrite.h
+++ b/src/common/readwrite.h
@@ -22,7 +22,9 @@ extern void try_fputc(uint8_t c, FILE * file, char * f);
 
 /* Wrapper to calling fgetc() and fgets() from function "f". The return code is
  * returned unless ferror() indicates an error (i.e. to signify an end of file,
- * fgetc() may return an EOF and fgets() a NULL).
+ * fgetc() may return an EOF and fgets() a NULL). try_fgetc() calls clearerr()
+ * on "file" before fgetc(), because some Unixes fgetc() remember old EOFs and
+ * only return those until explicitely cleared.
  */
 extern int try_fgetc(FILE * file, char * f);
 extern char * try_fgets(char * line, int size, FILE * file, char * f);