Maximum filename??

from limits.h

PATH_MAX 255
NAME_MAX 48

hence path name can be 255 characters
base file name can only be 48 characters

hence fp = fopen(“123456789012345678901234567890123456789012345678901234567890.txt”, “wb”); is not possible

the b in “wb” is redundant. No such thing as text and binary files in QNX