1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
|
/* fopenv.c : this function attempts to open a file based on the
* environment variable if an fopen in the current directory fails.
* The environment string can have ";" as separators for multiple
* path searching. Returns a NULL pointer if unsuccessful.
*/
#include <stdio.h>
#include <ctype.h>
#include "xtdio.h"
/* -----------------------------------------------------------------------
* Definitions:
*/
#ifdef unix
#define PATHSEP ':'
#else
#define PATHSEP ';'
#endif
/* -----------------------------------------------------------------------
* Source Code:
*/
/* fopenv: opens file for read/write based on environment variable
* char *filename : name of file to be opened
* char *ctrl : "r", "w", etc.
* char *env_var : environment variable to be used
*/
#ifdef __PROTOTYPE__
FILE *fopenv(
char *filename,
char *ctrl,
char *env_var)
#else /* __PROTOTYPE__ */
FILE *fopenv(filename,ctrl,env_var)
char *filename,*ctrl,*env_var;
#endif /* __PROTOTYPE__ */
{
char *s,*env,*buf;
int more;
FILE *fp;
/* see if file can be opened in current directory first */
fp= fopen(filename,ctrl);
if(fp) {
return fp;
}
/* check out the environment variable */
env= getenv(env_var);
/* attempt to open filename using environment search */
if(env) while(*env) { /* while there's environment-variable info left... */
for(s= env; *s && *s != PATHSEP; ++s);
more= *s == PATHSEP;
*s = '\0';
buf= calloc((size_t) strlen(env) + strlen(filename) + 2,sizeof(char));
#ifdef vms
sprintf(buf,"%s%s",env,filename);
#endif
#ifdef unix
sprintf(buf,"%s/%s",env,filename);
#endif
#ifdef LATTICE
sprintf(buf,"%s\\%s",env,filename);
#endif
#ifdef DESMET
sprintf(buf,"%s\\%s",env,filename);
#endif
#ifdef AZTEC_C
sprintf(buf,"%s/%s",env,filename);
#endif
#ifdef MSDOS
sprintf(buf,"%s\\%s",env,filename);
#endif
/* attempt to open file given the path */
fp= fopen(buf,ctrl);
/* free up memory */
free(buf);
if(fp) { /* successfully opened file */
return fp;
}
if(more) { /* another path to search */
*s= PATHSEP;
env= s + 1;
}
else env= s;
}
/* return NULL pointer, thereby indicating a modest lack of success */
return (FILE *) NULL;
}
|
