c++ - glibc sprintf 可以在可重入函数中使用吗？

Question

如果它写入本地缓冲区，我可以在可重入函数中使用 sprintf 吗？像这样:

void reentrant_function () { 
    int i = 4;
    char buffer[20];
    snprintf(buffer, 20, "%d", i); 
}

Answer 1

我来到这个页面是因为我也在问同样的问题。这是我从书上读到的:

UNIX 环境高级编程:第二版

Section 10.6

Most functions that are not in Figure 10.4 (a list of reentrant functions) are missing because (a) they are known to use static data structures, (b) they call malloc or free, or (c) they are part of the standard I/O library.

Linux 编程接口(interface)

Chapter 21.1.2

Functions can also be nonreentrant if they use static data structures for theirinternal bookkeeping. The most obvious examples of such functions are the membersof the stdio library (printf(), scanf(), and so on), which update internal datastructures for buffered I/O.

我想这取决于实现。这也取决于你如何实际使用 snprintf (缓冲区是必不可少的)。对该问题最安全的回答应该是“否”。