| Issue |
175136
|
| Summary |
clang-analyzer-unix.Errno produces false positive with certain uses of getcwd
|
| Labels |
false-positive
|
| Assignees |
|
| Reporter |
lultimouomo
|
clang-tidy 21 produces a false positive clang-analyzer-unix.Errno warning when `errno` is checked after `getcwd` fails, but only if the buffer passed to `getcwd` needs to be casted to `char*`.
```
#include <unistd.h>
#include <iostream>
#include <vector>
int main(int argc, char *argv[]) {
std::vector<char> charbuf(2);
while(1) {
if (!getcwd(charbuf.data(), charbuf.size() -1)) {
// No warning here
if (errno == ERANGE) {
charbuf.resize(charbuf.size() + 64);
continue;
}
}
break;
}
std::cout << charbuf.data() << std::endl;
std::vector<unsigned char> ucharbuf(2);
while(1) {
if (!getcwd((char*)ucharbuf.data(), ucharbuf.size() -1)) {
// warning: An undefined value may be read from 'errno' [clang-analyzer-unix.Errno]
if (errno == ERANGE) {
ucharbuf.resize(ucharbuf.size() + 64);
continue;
}
}
break;
}
std::cout << (const char*)ucharbuf.data() << std::endl;
return 0;
}
```
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