BUG: Warning when compiling tests

[alejandro-colomar]

$ make tests
gcc -O3 -I./src -o test/anim test/anim.c gnuplot_i.o
gcc -O3 -I./src -o test/example test/example.c gnuplot_i.o
gcc -O3 -I./src -lm -o test/png test/png.c gnuplot_i.o
test/png.c: In function ‘main’:
test/png.c:42:53: warning: passing argument 6 of ‘gnuplot_plot_x_multi_y’ from incompatible pointer type [-Wincompatible-pointer-types]
   42 |  gnuplot_plot_x_multi_y(g, x, y, N_POINTS, N_LINES, t);
      |                                                     ^
      |                                                     |
      |                                                     char **
In file included from test/png.c:7:
./src/gnuplot_i.h:408:18: note: expected ‘const char **’ but argument is of type ‘char **’
  408 |     const char** title);
      |     ~~~~~~~~~~~~~^~~~~

This is without changing the Makefile

[alejandro-colomar]

If I add -Wall -Wextra, you get all this:

$ make tests
gcc -O3 -I./src -Wall -Wextra -c -o gnuplot_i.o src/gnuplot_i.c
gcc -O3 -I./src -Wall -Wextra -o test/anim test/anim.c gnuplot_i.o
test/anim.c: In function ‘main’:
test/anim.c:14:14: warning: unused parameter ‘argc’ [-Wunused-parameter]
   14 | int main(int argc, char *argv[])
      |          ~~~~^~~~
test/anim.c:14:26: warning: unused parameter ‘argv’ [-Wunused-parameter]
   14 | int main(int argc, char *argv[])
      |                    ~~~~~~^~~~~~
gcc -O3 -I./src -Wall -Wextra -o test/example test/example.c gnuplot_i.o
test/example.c: In function ‘main’:
test/example.c:15:14: warning: unused parameter ‘argc’ [-Wunused-parameter]
   15 | int main(int argc, char *argv[])
      |          ~~~~^~~~
test/example.c:15:26: warning: unused parameter ‘argv’ [-Wunused-parameter]
   15 | int main(int argc, char *argv[])
      |                    ~~~~~~^~~~~~
gcc -O3 -I./src -Wall -Wextra -lm -o test/png test/png.c gnuplot_i.o
test/png.c: In function ‘main’:
test/png.c:42:53: warning: passing argument 6 of ‘gnuplot_plot_x_multi_y’ from incompatible pointer type [-Wincompatible-pointer-types]
   42 |  gnuplot_plot_x_multi_y(g, x, y, N_POINTS, N_LINES, t);
      |                                                     ^
      |                                                     |
      |                                                     char **
In file included from test/png.c:7:
./src/gnuplot_i.h:408:18: note: expected ‘const char **’ but argument is of type ‘char **’
  408 |     const char** title);
      |     ~~~~~~~~~~~~~^~~~~
test/png.c:12:14: warning: unused parameter ‘argc’ [-Wunused-parameter]
   12 | int main(int argc, char * argv[])
      |          ~~~~^~~~
test/png.c:12:27: warning: unused parameter ‘argv’ [-Wunused-parameter]
   12 | int main(int argc, char * argv[])
      |                    ~~~~~~~^~~~~~