I want to use color attributes in ncurses mode. But as stated in the topic, has_colors() returns false, meaning that the terminal does not support color manipulation. But using printf() and ansi color codes (not in ncurses mode), I can print color texts. I think this means that the terminal supports color manipulation. Am I wrong? What is the problem?
This is the code I use:
int main()
{
initscr();
if (has_colors() == false)
{
endwin();
printf("No color support!\n");
return -1;
}
start_color();
init_pair(1, COLOR_RED, COLOR_BLACK);
attron(COLOR_PAIR(1));
printw("This is a test!");
attroff(COLOR_PAIR(1));
endwin();
return 0;
}
Terminal configuration in ncurses comes from two flavours, depending on if ncurses was compiled with terminfo support or termcap support.
Either way, has_colors() is a function that consults the curses database (a terminal controls database based on how your terminal behaves) based on the value you use for your TERM environment variable.
A value of xterm is possible to include no color controls and probably what is making your terminal software not able to display colors. Just change your TERM variable to something like:
TERM=xterm-color
and try again. That terminal definition includes color support and makes has_colors() to return true.
from my own termcap file (based on a FreeBSD 12.1 system):
xterm-clear:\
:te=\E[?1049l:ti=\E[?1049h:\
:tc=xterm-new:
xterm-new|modern xterm:\
:@7=\EOF:@8=\EOM:F1=\E[23~:F2=\E[24~:K2=\EOE:Km=\E[M:\
:k1=\EOP:k2=\EOQ:k3=\EOR:k4=\EOS:k5=\E[15~:k6=\E[17~:\
:k7=\E[18~:k8=\E[19~:k9=\E[20~:k;=\E[21~:kI=\E[2~:\
:kN=\E[6~:kP=\E[5~:kd=\EOB:kh=\EOH:kl=\EOD:kr=\EOC:ku=\EOA:\
:tc=xterm-basic:
#
# This chunk is used for building the VT220/Sun/PC keyboard variants.
xterm-basic|modern xterm common:\
:am:bs:km:mi:ms:ut:xn:AX:\
:Co#8:co#80:kn#12:li#24:pa#64:\
:AB=\E[4%dm:AF=\E[3%dm:AL=\E[%dL:DC=\E[%dP:DL=\E[%dM:\
:DO=\E[%dB:LE=\E[%dD:RI=\E[%dC:UP=\E[%dA:ae=\E(B:al=\E[L:\
:as=\E(0:bl=^G:cd=\E[J:ce=\E[K:cl=\E[H\E[2J:\
:cm=\E[%i%d;%dH:cs=\E[%i%d;%dr:ct=\E[3g:dc=\E[P:dl=\E[M:\
:ei=\E[4l:ho=\E[H:im=\E[4h:is=\E[!p\E[?3;4l\E[4l\E>:\
:kD=\E[3~:kb=^H:ke=\E[?1l\E>:ks=\E[?1h\E=:kB=\E[Z:le=^H:md=\E[1m:\
:me=\E[m:ml=\El:mr=\E[7m:mu=\Em:nd=\E[C:op=\E[39;49m:\
:rc=\E8:rs=\E[!p\E[?3;4l\E[4l\E>:sc=\E7:se=\E[27m:sf=^J:\
:so=\E[7m:sr=\EM:st=\EH:\
:ue=\E[24m:up=\E[A:us=\E[4m:ve=\E[?12l\E[?25h:vi=\E[?25l:vs=\E[?12;25h:
# The xterm-new description has all of the features, but is not completely
# compatible with vt220. If you are using a Sun or PC keyboard, set the
# sunKeyboard resource to true:
# + maps the editing keypad
# + interprets control-function-key as a second array of keys, so a
# 12-fkey keyboard can support vt220's 20-fkeys.
# + maps numeric keypad "+" to ",".
# + uses DEC-style control sequences for the application keypad.
#
xterm-vt220|xterm emulating vt220:\
:*6=\E[4~:@7=\E[4~:K2=\EOu:Km=\E[M:kH=\E[4~:kh=\E[1~:\
:tc=xterm-basic:
xterm-24|xterms|vs100|24x80 xterm:\
:li#24:tc=xterm-old:
xterm-65|65x80 xterm:\
:li#65:tc=xterm-old:
xterm-bold|xterm with bold for underline:\
:so=\E[7m:us=\E[1m:tc=xterm-old:
xterm-boldso|xterm with bold for standout:\
:se=\E[m:so=\E[1m:tc=xterm-old:
xterm-mono|monochrome xterm:\
:ut@:\
:Co@:NC@:kn#20:pa@:\
:AB@:AF@:Sb@:Sf@:op@:st@:tc=xterm-old:
#
# Alternate terminal description that "works" for interactive shells such as
# tcsh and bash.
xterm-noapp|xterm with cursor keys in normal mode:\
:kd=\E[B:ke=\E>:kl=\E[D:kr=\E[C:ks=\E=:ku=\E[A:te@:ti@:\
:tc=xterm:
#
# This should work for the commonly used "color xterm" variations (XFree86
# xterm, color_xterm, nxterm, rxvt). Note that it does not set 'bce', so for
# XFree86 and rxvt, some applications that use colors will be less efficient,
# and in a few special cases (with "smart" optimization) the wrong color will
# be painted in spots.
xterm-color|generic "ANSI" color xterm:\
:Co#8:NC@:pa#64:\
:AB=\E[4%dm:AF=\E[3%dm:ac=:op=\E[m:tc=xterm-r6:
#
# These aliases are for compatibility with the terminfo; termcap cannot provide
# the extra features such as color initialization, but termcap applications
# still want the names.
xterm-16color|xterm alias 1:\
:tc=xterm-new:
xterm-88color|xterm alias 2:\
:Co#88:pa#7744:tc=xterm-256color:
xterm-256color|xterm alias 3:\
:Co#256:pa#32767:\
:AB=\E[48;5;%dm:AF=\E[38;5;%dm:tc=xterm-new:
xterm-nrc|xterm alias 4:\
:tc=xterm:
xterm-rep|xterm alias 5:\
:tc=xterm:
xterm-xmc|xterm alias 6:\
:sg#1:tc=xterm:
#
# An 8-bit description is doable with termcap, but there are probably no
# termcap (or BSD curses) applications that are able to use it.
#
# Add the capability to "clear the screen" after exiting vi, more/less, etc.
#
xterm-8bit-clear:\
:te=\233?1049l:ti=\233?1049h:ue=\23324m:\
:tc=xterm-8bit:
xterm-8bit|xterm terminal emulator 8-bit controls (X Window System):\
:am:km:mi:ms:xn:\
:co#80:it#8:li#24:\
:AL=\233%dL:DC=\233%dP:DL=\233%dM:DO=\233%dB:IC=\233%d@:\
:K2=\217y:Km=\233M:LE=\233%dD:RI=\233%dC:UP=\233%dA:\
:ae=\E(B:al=\233L:as=\E(0:bl=^G:bt=\233Z:cd=\233J:ce=\233K:\
:cl=\233H\2332J:cm=\233%i%d;%dH:cr=^M:cs=\233%i%d;%dr:\
:ct=\2333g:dc=\233P:dl=\233M:do=^J:ei=\2334l:ho=\233H:\
:im=\2334h:\
:is=\E[62"p\E G\233m\233?7h\E>\E7\233?1;3;4;6l\2334l\233r\E8:\
:k1=\23311~:k2=\23312~:k3=\23313~:k4=\23314~:k5=\23315~:\
:k6=\23317~:k7=\23318~:k8=\23319~:k9=\23320~:kD=\2333~:\
:kI=\2332~:kN=\2336~:kP=\2335~:kb=^H:kd=\217B:\
:ke=\233?1l\E>:kh=\2331~:kl=\217D:kr=\217C:ks=\233?1h\E=:\
:ku=\217A:le=^H:mb=\2335m:md=\2331m:me=\233m:mr=\2337m:\
:nd=\233C:rc=\E8:sc=\E7:se=\23327m:sf=^J:so=\2337m:sr=\215:\
:st=\210:ta=^I:ue=\23324m:\
:up=\233A:us=\2334m:vb=\233?5h\233?5l:ve=\233?25l\233?25h:\
:vs=\233?12;25h:vi=\233?25l:
#
xterm-hp|xterm with hpterm function keys:\
:@7=\EF:k1=\Ep:k2=\Eq:k3=\Er:k4=\Es:k5=\Et:k6=\Eu:k7=\Ev:\
:k8=\Ew:kC=\EJ:kD=\EP:kI=\EQ:kN=\ES:kP=\ET:kd=\EB:kh=\Eh:\
:kl=\ED:kr=\EC:ku=\EA:tc=xterm-basic:
#
xterm-sco|xterm with SCO function keys:\
:@7=\E[F:F1=\E[W:F2=\E[X:F3=\E[Y:F5=\E[a:F6=\E[b:F7=\E[c:\
:F8=\E[d:F9=\E[e:FA=\E[f:FB=\E[g:FC=\E[h:FD=\E[i:FE=\E[j:\
:FF=\E[k:ac=:k1=\E[M:k2=\E[N:k3=\E[O:k4=\E[P:k5=\E[Q:\
:k6=\E[R:k7=\E[S:k8=\E[T:k9=\E[U:k;=\E[V:kD=\177:kI=\E[L:\
:kN=\E[G:kP=\E[I:kd=\E[B:kh=\E[H:kl=\E[D:kr=\E[C:ku=\E[A:\
:tc=xterm-basic:
#
xterm-vt52|xterm emulating vt52:\
:bs:\
:co#80:it#8:li#24:\
:ae=\EG:as=\EF:bl=^G:cd=\EJ:ce=\EK:cl=\EH\EJ:cm=\EY%+ %+ :\
:cr=^M:do=\EB:ho=\EH:kb=^H:kd=\EB:kl=\ED:kr=\EC:ku=\EA:\
:le=\ED:nd=\EC:nw=^M^J:sf=^J:sr=\EI:ta=^I:up=\EA:
#
xterm-sun|xterm with Sun functionkeys:\
:%1=\E[196z:&8=\E[195z:@0=\E[200z:@5=\E[197z:@7=\E[220z:\
:F1=\E[192z:F2=\E[193z:K2=\E[218z:Km=\E[M:k1=\E[224z:\
:k2=\E[225z:k3=\E[226z:k4=\E[227z:k5=\E[228z:k6=\E[229z:\
:k7=\E[230z:k8=\E[231z:k9=\E[232z:k;=\E[233z:kD=\E[3z:\
:kI=\E[2z:kN=\E[222z:kP=\E[216z:kh=\E[214z:\
:tc=xterm-basic:
#
# vi may work better with this entry, because vi doesn't use insert mode much.
# |xterm-ic|xterm-vi|xterm with insert character instead of insert mode:\
xterm-ic|xterm-vi|xterm with insert char:\
:mi@:\
:IC=\E[%d@:ei@:ic=\E[@:im@:tc=xterm:
#
# Compatible with the X11R6.3 xterm
#
# Add the capability to "clear the screen" after exiting vi, more/less, etc.
#
xterm-r6-clear:\
:te=\E[2J\E[?47l\E8:ti=\E7\E[?47h:ue=\E[m:\
:tc=xterm-r6:
xterm-r6|xterm-old|X11R6 xterm:\
:am:bs:km:mi:ms:pt:xn:\
:co#80:kn#20:li#24:\
:*6=\E[4~:@0=\E[1~:@7=\E[4~:AL=\E[%dL:DC=\E[%dP:DL=\E[%dM:\
:DO=\E[%dB:F1=\E[23~:F2=\E[24~:F3=\E[25~:F4=\E[26~:\
:F5=\E[28~:F6=\E[29~:F7=\E[31~:F8=\E[32~:F9=\E[33~:\
:FA=\E[34~:LE=\E[%dD:RI=\E[%dC:UP=\E[%dA:ae=^O:al=\E[L:\
:as=^N:bl=^G:cd=\E[J:ce=\E[K:cl=\E[H\E[2J:cm=\E[%i%d;%dH:\
:cs=\E[%i%d;%dr:ct=\E[3g:dc=\E[P:dl=\E[M:eA=\E)0:ei=\E[4l:\
:ho=\E[H:im=\E[4h:\
:is=\E[m\E[?7h\E[4l\E>\E7\E[r\E[?1;3;4;6l\E8:\
:k1=\E[11~:k2=\E[12~:k3=\E[13~:k4=\E[14~:k5=\E[15~:\
:k6=\E[17~:k7=\E[18~:k8=\E[19~:k9=\E[20~:k;=\E[21~:\
:kD=\E[3~:kI=\E[2~:kN=\E[6~:kP=\E[5~:kb=^H:kd=\EOB:\
:ke=\E[?1l\E>:kh=\E[1~:kl=\EOD:kr=\EOC:ks=\E[?1h\E=:\
:ku=\EOA:md=\E[1m:me=\E[m:ml=\El:mr=\E[7m:mu=\Em:nd=\E[C:\
:rc=\E8:rs=\E[m\E[?7h\E[4l\E>\E7\E[r\E[?1;3;4;6l\E8:\
:sc=\E7:se=\E[m:sf=^J:so=\E[7m:sr=\EM:\
:ue=\E[m:up=\E[A:us=\E[4m:
#
# Compatible with the R5 xterm
#
# Add the capability to "clear the screen" after exiting vi, more/less, etc.
#
xterm-r5-clear:\
:te=\E[2J\E[?47l\E8:ti=\E7\E[?47h:ue=\E[m:\
:tc=xterm-r5:
xterm-r5|X11R5 xterm X11R5:\
:am:bs:km:mi:ms:pt:xn:\
:co#80:kn#4:li#24:\
:@7=\E[4~:AL=\E[%dL:DC=\E[%dP:DL=\E[%dM:DO=\E[%dB:\
:IC=\E[%d@:UP=\E[%dA:al=\E[L:cd=\E[J:ce=\E[K:cl=\E[H\E[2J:\
:cm=\E[%i%d;%dH:cs=\E[%i%d;%dr:ct=\E[3g:dc=\E[P:dl=\E[M:\
:ei=\E[4l:ho=\E[H:im=\E[4h:\
:is=\E[r\E[m\E[2J\E[H\E[?7h\E[?1;3;4;6l\E[4l:\
:k1=\E[11~:k2=\E[12~:k3=\E[13~:k4=\E[14~:kb=^H:kd=\EOB:\
:ke=\E[?1l\E>:kh=\E[1~:kl=\EOD:kr=\EOC:ks=\E[?1h\E=:\
:ku=\EOA:md=\E[1m:me=\E[m:mr=\E[7m:nd=\E[C:rc=\E8:\
:rs=\E>\E[?1;3;4;5;6l\E[4l\E[?7h\E[m\E[r\E[2J\E[H:\
:sc=\E7:se=\E[m:sf=^J:so=\E[7m:sr=\EM:\
:up=\E[A:us=\E[4m:
#
# Customization begins here.
xterm-xfree86|xterm terminal emulator (XFree86):\
:tc=xterm-new:
#
# This is the only entry which you should have to customize, since "xterm"
# is widely used for a variety of incompatible terminal emulations including
# color_xterm and rxvt.
xterm|X11 terminal emulator:\
:tc=xterm-new:
# :tc=xterm-r6: