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This does not apply to the character argument in putc(), which is guaranteed to be evaluated exactly once.

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Noncompliant Code Example (getc)

This code calls the getc() function with an expression as the stream argument. If getc() is implemented as a macro, the file may be opened several times (see FIO31-C. Do not simultaneously open the same file multiple times).

char *file_name;
FILE *fptr;

/* initialize file_name */

int c = getc(fptr = fopen(file_name, "r"));
if (c == EOF) {
  /* Handle error */
}

This non-compliant noncompliant code example also violates FIO33-C. Detect and handle input output errors resulting in undefined behavior because the value returned by fopen() is not checked for errors.

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int c;
char *file_name;
FILE *fptr;

/* initialize file_name */

fptr = fopen(file_name, "r");
if (fptr == NULL) {
  /* Handle error */
}

c = getc(fptr);
if (c == EOF) {
  /* Handle error */
}

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Noncompliant Code Example (putc)

In this non-compliant noncompliant example, putc() is called with an expression as the stream argument. If putc() is implemented as a macro, the expression can be evaluated several times within the macro expansion of putc() with unintended results.

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The LDRA tool suite V 7.6.0 is able to can detect violations of this rule.

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