I have encountered unexpected behaviour with open_memstream(). Below
is a test case that shows the problem. Shouldn't each invocation of
open_memstream() create a a stream in the same initial state?
Shouldn't 'B' be written to the beginning of the buffer?
I am running Windows 7 Professional Ver 6.1 Build 7601 Service Pack 1
on an 8 processor amd64. My cygwin DLL version is 1.7.28. I am running
the 32-bit install.
Actual output:
test: A
buf: 41 0 0 0 0 0 0 0 0 0
test: B
buf: 0 42 0 0 0 0 0 0 0 0
assertion "0 == strcmp(msg, buf)" failed: file
"test_open_memstream.c", line 33, function: Test
Aborted (core dumped)
Expected output:
test: A
buf: 41 0 0 0 0 0 0 0 0 0
test: B
buf: 42 0 0 0 0 0 0 0 0 0
Test program for GCC 4.8.2 (gcc -Wall -Wextra -pedantic -g
test_open_memstream.c):
#include <assert.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
FILE* RS232_1_tx = 0;
void printbuf(char* buf){
int i = 0;
printf("buf: ");
for (i = 0; i < 10; ++i) {
printf("%x ", buf[i]); }
printf("\n"); }
void io_operations(char* msg){
fprintf(RS232_1_tx, msg); }
void Test(char* msg) {
char* buf = 0;
size_t size = 0;
printf("test: %s\n", msg);
RS232_1_tx = open_memstream(&buf, &size);
/* Following fseek required to work around suspected bug in the lib. */
/* fseek(RS232_1_tx, 0, SEEK_SET); */
assert(RS232_1_tx);
io_operations(msg);
fflush(RS232_1_tx);
printbuf(buf);
assert(0 == strcmp(msg, buf));
fclose(RS232_1_tx);
RS232_1_tx = 0;
free(buf); }
int main() {
Test("A");
Test("B");
return 0; }
--
Adam Burry
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