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The rewind function is obsolete because rewind does not return a value and can be emulated using fseek. See FIO07-C. Prefer fseek() to rewind().

Unchecked Obsolete Functions

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In this noncompliant code example, the obsolete functions strcat and strcpy are () and strcpy() are used.

void complain(const char *msg) {
  static const char prefix[] = "Error: ";
  static const char suffix[] = "\n";
  char buf[BUFSIZE];

  strcpy(buf, prefix);
  strcat(buf, msg);
  strcat(buf, suffix);
  fputs(buf, stderr);
}

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enum { BUFFERSIZE=256 };

void complain(const char *msg) {
  static const char prefix[] = "Error: ";
  static const char suffix[] = "\n";
  char buf[BUFFERSIZE];

  strcpy_s(buf, BUFFERSIZE, prefix);
  strcat_s(buf, BUFFERSIZE, msg);
  strcat_s(buf, BUFFERSIZE, suffix);
  fputs(buf, stderr);
}

Noncompliant Code Example

In this noncompliant code example, the obsolete function setbuf is used.

FILE *file;
/* Setup file */
setbuf(file, NULL);
/* ... */

Compliant Solution

In this compliant solution, function setvbuf is used instead.

FILE *file;
/* Setup file */
setvbuf(file, NULL, _IONBF, BUFSIZ);
/* ... */

Noncompliant Code Example

In this noncompliant code example, tmpnam is used.

char file_name[L_tmpnam];
FILE *fp;

if (!tmpnam(file_name)) {
  /* Handle error */
}

/* A TOCTOU race condition exists here */

fp = fopen(file_name, "wb+");
if (fp == NULL) {
   /* Handle error */
}

Compliant Solution

In this compliant solution, mkostemp is used instead.

static const char temp_file_template[] = TEMP_DIR DIR_SEPARATOR "xyzzy_XXXXXX";
char file_name[sizeof(temp_file_template)];
FILE *fp;
int fd;

strcpy_s(file_name, sizeof(temp_file_template), temp_file_template);
fd = mkostemp(file_name, O_RDWR | O_CREAT | O_TRUNC);
if (fd == -1) {
  /* Handle error */
}

fp = fdopen(fd, "wb+");
if (fp == NULL) {
   /* Handle error */
}

Noncompliant Code Example

In this noncompliant code example, tmpfile is used.

FILE *fp = tmpfile();
if (fp == NULL) {
  /* Handle error */
}

Compliant Solution

In this compliant solution,

Exceptions

MSC34-EX1: If an out-of-bounds store cannot occur in a specific invocation of a function, the invocation of that function is permitted by this rule. The rationale for this exception is that the simple use of such a function in a program does not mean the program is incorrect. To eliminate the use of such a function, the programmer must replace calls to the deprecated or obsolete function with calls to the alternative functions. Unfortunately, the process of modifying existing code frequently introduces defects and vulnerabilities and is not recommended. New code should be developed in conformance to this guideline, however.

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