Hi all, I have recently ran into a problem with Cygwin accessing files located in shared folders. The attached program does fwrite() and then checks file size with ftell(). Ftell() returns correct results in any of following situations: 1) I access local file: c:/test.bin 2) I access file via UNC-address from the same computer: //server-name/dir/test.out gribov.y@s-cw-head ~/build/upc/opt $ ./a.exe success
But when I try to access file via UNC-address from a different machine ftell() starts returning 0 instead of expected 8: gribov.y@s-cw-head ~/build/upc/opt $ gcc io.c && run_ms_job -n 1 -network smp a.exe ftell(p) == sizeof(data) failed at io.c:26 Note that the file is created and data is written correctly: gribov.y@s-cw-head ~/build/upc/opt $ xxd ~/pgas/test.bin 0000000: ffff ffff ffff ffff ........ so there seem to be a problem with ftell() itself. Any help/ideas will be much appreciated. I have tried searching the MLs but have not found anything similiar to my problem. -Yuri
cygcheck.out
Description: Binary data
#include <stdio.h>
#include <stdlib.h>
#include <fcntl.h>
#define CHECK(cond) if( !(cond) ) { printf("%s failed at %s:%d\n", #cond, __FILE__, __LINE__); exit(1); }
const char *fname = "//s-cw-head/pgas/test.bin"; // Works with simple "c:/test.bin"
int main() {
// Without this snippet everything works
int perm = S_IRUSR | S_IWUSR | S_IRGRP | S_IWGRP | S_IROTH | S_IWOTH;
int mode = O_WRONLY | O_CREAT | O_TRUNC;
int fd = open(fname, mode, perm);
CHECK( -1 != fd );
close(fd);
// Main part
FILE *p = fopen(fname, "rb+");
CHECK(p);
long long data = -1;
CHECK( sizeof(data) == fwrite(&data, 1, sizeof(data), p) );
CHECK( 0 == fseek(p, 0, SEEK_END) );
CHECK( ftell(p) == sizeof(data) );
printf("success\n");
return 0;
}
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