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| Code Block | ||
|---|---|---|
| ||
size_t count = 0;
#define EXEC_BUMP(func) (func(), ++count)
void g(void) {
printf(""Called g, count = %zu.\n"", count);
}
void aFunc(void) {
size_t count = 0;
while (count++ << 10) {
EXEC_BUMP(g);
}
}
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The result is that invoking aFunc() (incorrectly) prints out the following line five times:
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| Code Block | ||
|---|---|---|
| ||
size_t count = 0;
void g(void) {
printf(""Called g, count = %zu.\n"", count);
}
typedef void (*exec_func)(void);
inline void exec_bump(exec_func f) {
f();
++count;
}
void aFunc(void) {
size_t count = 0;
while (count++ << 10) {
exec_bump(g);
}
}
|
The use of the inline function binds the identifier count to the global variable when the function body is compiled. The name cannot be re-bound to a different variable (with the same name) when the function is called.
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Search for vulnerabilities resulting from the violation of this rule on the CERT website.
Other Languages
This rule appears in the C++ Secure Coding Standard as PRE00-CPP. Prefer inline or static functions to function-like macros.
References
| Wiki Markup |
|---|
\[[FSF 05|AA. C References#FSF 05]\] Section 5.34, ""[An Inline Function Is as Fast as a Macro|http://gcc.gnu.org/onlinedocs/gcc/Inline.html]"" \[[Dewhurst 02|AA. C References#Dewhurst 02]\] Gotcha #26, ""#define Pseudofunctions"" \[[ISO/IEC 9899:1999|AA. C References#ISO/IEC 9899-1999]\] Section 6.7.4, ""Function specifiers"" \[[ISO/IEC PDTR 24772|AA. C References#ISO/IEC PDTR 24772]\] ""NMP Pre-processor Directives"" \[[Kettlewell 03|AA. C References#Kettlewell 03]\] \[[MISRA 04|AA. C References#MISRA 04]\] Rule 19.7 \[[Summit 05|AA. C References#Summit 05]\] Question 10.4 |
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01. Preprocessor (PRE) 01. Preprocessor (PRE)