LINT(1) LINT(1) NAME lint - a C program verifier SYNOPSIS lint [ -abchnpuvx ] file ... DESCRIPTION _L_i_n_t attempts to detect features of the C program _f_i_l_e_s which are likely to be bugs, or non-portable, or wasteful. It also checks the type usage of the program more strictly than the compilers. Among the things which are currently found are unreachable statements, loops not entered at the top, automatic variables declared and not used, and log‐ ical expressions whose value is constant. Moreover, the usage of func‐ tions is checked to find functions which return values in some places and not in others, functions called with varying numbers of arguments, and functions whose values are not used. By default, it is assumed that all the _f_i_l_e_s are to be loaded together; they are checked for mutual compatibility. Function definitions for certain libraries are available to _l_i_n_t; these libraries are referred to by a conventional name, such as ‘-lm’, in the style of _l_d(1). Argu‐ ments ending in _._l_n are also treated as library files. To create lint libraries, use the -C option: lint -Cfoo files . . . where _f_i_l_e_s are the C sources of library _f_o_o_. The result is a file _l_l_i_b_-_l_f_o_o_._l_n in the correct library format suitable for linting pro‐ grams using _f_o_o_. Any number of the options in the following list may be used. The -D, -U, and -I options of _c_c(1) are also recognized as separate arguments. p Attempt to check portability to the _I_B_M and _G_C_O_S dialects of C. h Apply a number of heuristic tests to attempt to intuit bugs, improve style, and reduce waste. b Report _b_r_e_a_k statements that cannot be reached. (This is not the default because, unfortunately, most _l_e_x and many _y_a_c_c out‐ puts produce dozens of such comments.) v Suppress complaints about unused arguments in functions. x Report variables referred to by extern declarations, but never used. a Report assignments of long values to int variables. c Complain about casts which have questionable portability. u Do not complain about functions and variables used and not defined, or defined and not used (this is suitable for running _l_i_n_t on a subset of files out of a larger program). n Do not check compatibility against the standard library. z Do not complain about structures that are never defined (e.g. using a structure pointer without knowing its contents.). _E_x_i_t(2) and other functions which do not return are not understood; this causes various lies. Certain conventional comments in the C source will change the behavior of _l_i_n_t: /*NOTREACHED*/ at appropriate points stops comments about unreachable code. /*VARARGS_n*/ suppresses the usual checking for variable numbers of arguments in the following function declaration. The data types of the first _n arguments are checked; a missing _n is taken to be 0. /*NOSTRICT*/ shuts off strict type checking in the next expression. /*ARGSUSED*/ turns on the -v option for the next function. /*LINTLIBRARY*/ at the beginning of a file shuts off complaints about unused functions in this file. AUTHOR S.C. Johnson. Lint library construction implemented by Edward Wang. FILES /usr/lib/lint/lint[12] programs /usr/lib/lint/llib-lc.ln declarations for standard functions /usr/lib/lint/llib-lc human readable version of above /usr/lib/lint/llib-port.ln declarations for portable functions /usr/lib/lint/llib-port human readable . . . llib-l*.ln library created with -C SEE ALSO cc(1) S. C. Johnson, _L_i_n_t_, _a _C _P_r_o_g_r_a_m _C_h_e_c_k_e_r BUGS There are some things you just can’’t get lint to shut up about. /*NOSTRICT*/ is not implemented in the current version (alas). 4th Berkeley Distribution March 17, 1986 LINT(1)