Q34305: Path Strings Need Double Backslashes or fopen/open Fails

Article: Q34305
Product(s): See article
Version(s): 3.00 4.00 5.00 5.10 | 5.10
Operating System(s): MS-DOS | OS/2
Keyword(s): ENDUSER | | mspl13_c
Last Modified: 27-OCT-1988

Problem:

According to Pages 444 and 274 of the "Microsoft C 5.10 Optimizing
Compiler Run-Time Library Reference," I should be able to specify the
path to the file that I want to open. However, I always receive a null
pointer, indicating an error, when I attempt to open a file that is
not in the current directory.

I am using the following fopen statement:

stream = fopen("d:\c\source\test.c", "r");

Response:

The following fopen statement will successfully open the file:

stream = fopen("d:\\c\\source\\test.c", "r");

Because the backslash has special meaning in C, it must be preceded by
an additional backslash. In the case of the first (unsuccessful)
example, a file named "d:csourcetest.c" actually is being searched for
in the current directory. In the second example, the correct directory
is searched for in the file "test.c".

The following other functions are among those that use path names as
input arguments:

chdir, mkdir, rmdir, access, chmod, remove, rename, splitpath, stat,
creat,  open, sopen, freopen, tempnam, execl, execle, execlp,
execlpe, execv, execve, execvp, execvpe, spawnl, spawnle, spawnlp,
spawnlpe, spawnv, spawnve, spawnvp, spawnvpe, system, _dos_creat,
_dos_creatnew, _dos_findfirst, _dos_getfileattr, _dos_open,
_dos_setfileattr, utime, putenv, _searchenv

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