如果我们查看 C 库 glibc 的目录 math ，我们有以下文件：
atest-exp2.c
atest-exp.c
atest-sincos.c
basic-test.c
bits
bug-nextafter.c
bug-nexttoward.c
bug-tgmath1.c
cabs.c
cabsf.c
cabsl.c
carg.c
cargf.c
cargl.c
cimag.c
cimagf.c
cimagl.c
complex.h
conj.c
conjf.c
conjl.c
creal.c
crealf.c
creall.c
divtc3.c
e_acoshl.c
e_acosl.c
e_asinl.c
e_atan2l.c
e_atanhl.c
e_coshl.c
e_exp10.c
e_exp10f.c
e_exp10l.c
e_exp2l.c
e_expl.c
e_fmodl.c
e_gammal_r.c
e_hypotl.c
e_j0l.c
e_j1l.c
e_jnl.c
e_lgammal_r.c
e_log10l.c
e_log2l.c
e_logl.c
e_powl.c
e_rem_pio2l.c
e_scalb.c
e_scalbf.c
e_scalbl.c
e_sinhl.c
e_sqrtl.c
fclrexcpt.c
fedisblxcpt.c
feenablxcpt.c
fegetenv.c
fegetexcept.c
fegetround.c
feholdexcpt.c
fenv.h
fesetenv.c
fesetround.c
feupdateenv.c
fgetexcptflg.c
fpu_control.c
fraiseexcpt.c
fsetexcptflg.c
ftestexcept.c
gen-libm-test.pl
ieee-math.c
k_cosl.c
k_rem_pio2l.c
k_sincosl.c
k_sinl.c
k_tanl.c
libm-test.inc
machine
Makefile
math.h
multc3.c
README.libm-test
s_asinhl.c
s_atanl.c
s_cacos.c
s_cacosf.c
s_cacosh.c
s_cacoshf.c
s_cacoshl.c
s_cacosl.c
s_casin.c
s_casinf.c
s_casinh.c
s_casinhf.c
s_casinhl.c
s_casinl.c
s_catan.c
s_catanf.c
s_catanh.c
s_catanhf.c
s_catanhl.c
s_catanl.c
s_cbrtl.c
s_ccos.c
s_ccosf.c
s_ccosh.c
s_ccoshf.c
s_ccoshl.c
s_ccosl.c
s_cexp.c
s_cexpf.c
s_cexpl.c
s_clog10.c
s_clog10f.c
s_clog10l.c
s_clog.c
s_clogf.c
s_clogl.c
s_cpow.c
s_cpowf.c
s_cpowl.c
s_cproj.c
s_cprojf.c
s_cprojl.c
s_csin.c
s_csinf.c
s_csinh.c
s_csinhf.c
s_csinhl.c
s_csinl.c
s_csqrt.c
s_csqrtf.c
s_csqrtl.c
s_ctan.c
s_ctanf.c
s_ctanh.c
s_ctanhf.c
s_ctanhl.c
s_ctanl.c
s_erfl.c
setfpucw.c
s_expm1l.c
s_fdim.c
s_fdimf.c
s_fdiml.c
s_fma.c
s_fmaf.c
s_fmal.c
s_fmax.c
s_fmaxf.c
s_fmaxl.c
s_fmin.c
s_fminf.c
s_fminl.c
s_ldexp.c
s_ldexpf.c
s_ldexpl.c
s_log1pl.c
s_nan.c
s_nanf.c
s_nanl.c
s_nextafter.c
s_nexttowardf.c
s_nexttowardl.c
s_significand.c
s_significandf.c
s_significandl.c
s_tanhl.c
test-double.c
test-fenv.c
test-float.c
test-fpucw.c
test-idouble.c
test-ifloat.c
test-ildoubl.c
test-ldouble.c
test-matherr.c
test-misc.c
test-powl.c
test-tgmath2.c
test-tgmath.c
test-tgmath-int.c
test-tgmath-ret.c
tgmath.h
t_sincosl.c
tst-CMPLX2.c
tst-CMPLX.c
tst-definitions.c
Versions
w_acos.c
w_acosf.c
w_acosh.c
w_acoshf.c
w_acoshl.c
w_acosl.c
w_asin.c
w_asinf.c
w_asinl.c
w_atan2.c
w_atan2f.c
w_atan2l.c
w_atanh.c
w_atanhf.c
w_atanhl.c
w_cosh.c
w_coshf.c
w_coshl.c
w_drem.c
w_dremf.c
w_dreml.c
w_exp10.c
w_exp10f.c
w_exp10l.c
w_exp2.c
w_exp2f.c
w_exp2l.c
w_expl.c
w_fmod.c
w_fmodf.c
w_fmodl.c
w_hypot.c
w_hypotf.c
w_hypotl.c
w_ilogb.c
w_ilogbf.c
w_ilogbl.c
w_j0.c
w_j0f.c
w_j0l.c
w_j1.c
w_j1f.c
w_j1l.c
w_jn.c
w_jnf.c
w_jnl.c
w_lgamma.c
w_lgammaf.c
w_lgammaf_r.c
w_lgammal.c
w_lgammal_r.c
w_lgamma_r.c
w_log10.c
w_log10f.c
w_log10l.c
w_log2.c
w_log2f.c
w_log2l.c
w_log.c
w_logf.c
w_logl.c
w_pow.c
w_powf.c
w_powl.c
w_remainder.c
w_remainderf.c
w_remainderl.c
w_scalb.c
w_scalbf.c
w_scalbl.c
w_sinh.c
w_sinhf.c
w_sinhl.c
w_sqrt.c
w_sqrtf.c
w_sqrtl.c
w_tgamma.c
w_tgammaf.c
w_tgammal.c
e_和s_前缀是什么w_意思？