12
C can do C++ - Like Destructors too!
Use this:
static inline void cln_fptr(FILE **f) {
fclose(*f);
}
static void foo(void) {
__attribute__((cleanup(cln_fptr))) FILE *f;
f = fopen("/etc/passwd", "r");
// [...]
}
#SecureCoding #C/C++
The RAII pattern in C++ is very convenient and helps avoiding certain types of bugs. Resource management is tied to the scope of stack objects and effectively handed over to compiler generated code. Forgetting to free a buffer or unlock a mutex is no longer an issue.
In C programs, a similar pattern can be achieved through a gcc extension. A stack
variable can specify a function to be called when it goes out of scope
using the __cleanup__ attribute. This approach is extensively used in large code
bases like systemd for RAII-style resource management.
Get in touch
sigma star gmbh
Eduard-Bodem-Gasse 6, 1st floor
6020 Innsbruck | Austria
