There was a requirement to include #!/bin/bash in the first line of all files in a project to create static libraries, but during compilation of the object file, the compiler gave me the message:
In file included from 0-isupper.c:1:
main.h:1:2: error: invalid preprocessing directive #!
1 | #!/bin/bash
| ^
The error indicated is the !
So, I want to know if header files do or do not contain shebang.
CodePudding user response：
A shebang line only belongs in executable (script) files. It is interpreted by the kernel when the file is executed. You'd have to be doing something like ./header.h to execute the header so that the kernel pays attention to the shebang line, and the header would have to be executable as well.
Header files should never be executable, so a header file has no need for a shebang line.
Further, as your compiler correctly pointed out, a shebang line (line 1 starting with #! is not valid C. The C preprocessor interprets the # as meaning 'there is a preprocessor directive after this', but no valid (standard) C preprocessor directive starts with a ! (bang).
It is not clear why creating static libraries would ever require a shebang line. I'd normally be using makefiles to control the building of libraries, and those don't usually have shebang in them. (If you use #!/usr/bin/make -f as the shebang, you can use it, but that's very, very non-standard.)
Consequently, there is some misunderstanding about the meaning of the instruction that there was "a requirement to include #!/bin/bash in the first line of all files in a project to create static libraries". However, there are at least two possibilities:
- Those promulgating the instruction didn't specify clearly what was intended and you misunderstood what they did specify.
- Those promulgating the instruction didn't understand what they were specifying.
It's more likely, I think, that you've misinterpreted their intention, possibly because you didn't read carefully enough or possibly because they did not specify what was intended carefully enough.
CodePudding user response：
No. Header files are read by a compiler. Shebang (#!) is used by the kernel to determine which binary to use to interpret the remaining part of the text file. Typically the binary is shell or other scripting languages like awk, javascript, perl, python, ruby etc.