github.com/afumu/libc@v0.0.6/musl/src/ctype/isalpha.c (about)

     1  #include <ctype.h>
     2  #undef isalpha
     3  
     4  int isalpha(int c)
     5  {
     6  	return ((unsigned)c|32)-'a' < 26;
     7  }
     8  
     9  int __isalpha_l(int c, locale_t l)
    10  {
    11  	return isalpha(c);
    12  }
    13  
    14  weak_alias(__isalpha_l, isalpha_l);